Method and apparatus for combining processing power of MIDI-enabled mobile stations to increase polyphony

ABSTRACT

A method for playing music having i note polyphony, as well as a system containing a plurality of sources and a source itself, with at least two sources of a group of sources, where a first source is assigned to play j notes and a second source is assigned to play k notes, where j&lt;i and k&lt;i, and where the notes are assigned in a predetermined order. For a case where j+k&lt;i, the methods further includes assigning a third source l additional notes to play of the musical composition. For a case where j+k_i, the l notes may duplicate all or some of the j or k notes played by the first or second sources. The j and k notes are played simultaneously, and the method further includes an initial step of synchronizing the first source to the second source through a wireless local network such as an RF network, e.g., a Bluetooth network, or an optical network. Preferably one of the at least two sources functions as a group master, and assigns an identification within the group to the other source or sources using the wireless local network.

TECHNICAL FIELD

[0001] The field of the invention is that of combining the processingpower of and synchronizing a plurality of simple computing andcommunications devices, such as cellular telephones, to increase thepolyphony of a song being played or other sound generation. Inparticular, these teachings relate to techniques for musicalcompositions and to wireless communications systems and methods.

BACKGROUND

[0002] A standard protocol for the storage and transmission of soundinformation is the MIDI (Musical Instrument Digital Interface) system,specified by MIDI Manufacturers Association. The invention is discussedin the context of MIDI for convenience because that is a well known,commercially available standard. Other standards could be used instead,and the invention is not confined to MIDI.

[0003] The information exchanged between two MIDI devices is musical innature. MIDI information informs a music synthesizer, in a most basicmode, when to start and stop playing a specific note. Other informationincludes, e.g. the volume and modulation of the note, if any. MIDIinformation can also be more hardware specific. It can inform asynthesizer to change sounds, master volume, modulation devices, and howto receive information. MIDI information can also be used to indicatethe starting and stopping points of a song or the metric position withina song. Other applications include using the interface between computersand synthesizers to edit and store sound information for the synthesizeron the computer.

[0004] The basis for MIDI communication is the byte, and each MIDIcommand has a specific byte sequence. The first byte of the MIDI commandis the status byte, which informs the MIDI device of the function toperform. Encoded in the status byte is the MIDI channel. MIDI operateson 16 different channels, numbered 1 through 16. MIDI units operate toaccept or ignore a status byte depending on what channel the unit is setto receive. Only the status byte has the MIDI channel number encoded,and all other bytes are assumed to be on the channel indicated by thestatus byte until another status byte is received.

[0005] A Network Musical Performance (NMP) occurs when a group ofmusicians, located at different physical locations, interact over anetwork to perform as they would if located in the same room. Referencein this regard can be had to a publication entitled “A Case for NetworkMusical Performance”, J. Lazzaro and J. Wawrzynek, NOSSDAV<01, Jun.25-26, 2001, Port Jefferson, N.Y., USA. These authors describe the useof a client/server architecture employing the IETF Real Time Protocol(RTP) to exchange audio streams by packet transmissions over a network.Related to this publication is another publication: “The MIDI WireProtocol Packetization (MWPP)”, also by J. Lazzaro and J. Wawrzynek,http://www.ietf.org/internet-drafts/draft-ietf-avt-mwpp-midi-rtp-02.txt,Internet Draft, Feb. 28, 2002 (expires Aug. 28, 2002).

[0006] General MIDI (GM) is a wide spread specification family intendedprimarily for consumer quality synthesizers and sound cards. Currentlythere exist two specifications: GM 1.0, “General MIDI Level 1.0”, MIDIManufacturers Association, 1996, and GM 2.0, “General MIDI Level 2.0”,MIDI Manufacturers Association, 1999. Unfortunately, thesespecifications require the use of high polyphony (24 and 32), as well asstrenuous sound bank requirements, making them less than optimum for usein low cost cellular telephones and other mobile stations.

[0007] In order to overcome these problems, the MIDI ManufacturersAssociation has established a Scalable MIDI working group that hasformulated a specification, referred to as SP-MIDI, that has become aninternational third generation (3G) standard for mobile communications.In order to have the most accurate references, this application willquote from the specification from time to time. SP-MIDI's polyphony andsound bank implementations are scalable, which makes the format bettersuited for use in mobile phones, PDAs and other similar devices.Reference with regard to SP-MIDI can be found at www.midi.org., morespecifically in a document entitled Scalable Polyphony MIDISpecification, The MIDI Manufacturers Association, Los Angeles, Calif.,and in a document entitled Scalable Polyphony MIDI Specification andDevice Profiles which is incorporated by reference herein.

[0008] As wireless telecommunications systems and terminals evolve ithas become desirable to provide high quality audio applications that runin this environment. Examples of applications are in providing users anability to listen to high quality music, as well as high quality soundgeneration, such as musical ringing tones for telephones.

SUMMARY OF THE INVENTION

[0009] The foregoing and other problems are overcome, and otheradvantages are realized, in accordance with the presently preferredembodiments of these teachings.

[0010] A method is herewith provided to allocate and partition thecomputational load of software synthesis between two or more sources.

[0011] The teachings of this invention provide an entertainmentapplication utilizing software synthesis and, preferably, the SP-MIDI ora similar standard. The use of SP-MIDI is not required, and is used asan example for convenience. Other protocols or standards could also beused. By the use of this invention one is enabled to combine the soundprocessing power of two or more sources in order to increase thepolyphony of a song being played. The sources are assumed to besynchronized to one another using, for example, a low power RF interfacesuch as Bluetooth, and the sources play the same MIDI file according tospecified rules, preferably rules specified by SP-MIDI or some otherMIDI-related protocol. MIDI is referred to for convenience because thatis a well known, commercially available standard. Other standards couldbe used instead, and the invention is not confined to MIDI.

[0012] Disclosed is a method for playing music, as well as a systemcontaining a plurality of sources and a source itself. The methodincludes providing a MIDI musical composition having i note polyphonyand playing the musical composition with at least two sources of a setof sources, where a first source is assigned to play j notes and asecond source is assigned to play k notes, where j<i and k<i, and wherethe notes are assigned in a Channel Priority Order. For a case wherej+k<i, the methods further includes assigning a third source ladditional notes to play of the musical composition. For a case wherej+k=i, the l notes may duplicate all or some of the j or k notes playedby the first or second sources.

[0013] The j and k notes are played simultaneously, and the methodfurther includes an initial step of synchronizing the first source tothe second source through a cable or wireless local network such as anRF network, e.g., a Bluetooth network, or an optical network.

[0014] Preferably one of the two sources functions as a group master,and assigns an identification within the group to the other source orsources, using the wireless local network.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The foregoing and other aspects of these teachings are made moreevident in the following Detailed Description of the PreferredEmbodiments, when read in conjunction with the attached Drawing Figures,wherein:

[0016]FIG. 1 is a high level block diagram showing a wirelesscommunication network comprised of a plurality of MIDI devices, such asone or more sources and one or more MIDI units, such as a synthesizer;

[0017]FIG. 2 is a simplified block diagram in accordance with thisinvention showing two of the sources from FIG. 1 that are MIDI enabled;

[0018]FIG. 3 is an exemplary state diagram illustrating the setting ofIDs when one device acts as a master device; and

[0019]FIG. 4 shows an example of how SP-MIDI synthesizers with differentpolyphony capabilities (SP-MIDInn) select which MIDI channels to play. Anumber of the highest priority MIDI channels are selected according tothe corresponding MIP values.

[0020]FIG. 5 shows a block level diagram of a mobile station.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021]FIG. 1 shows a wireless communication network 1 that includes aplurality of MIDI devices, such as one or more mobile telephoneapparatus (handsets) 10, one or MIDI units 12. The MIDI unit 12 could beor could contain a music synthesizer, a computer, or any device that hasMIDI capability. Illustratively, handsets 10 will contain a chip thatperforms the tasks of synthesis and associated software. The sources 10could include headphones (not shown), but preferably for a group playingsession as envisioned herein a speaker, such as the internal speaker 10Aor an external speaker 10B, is used for playing music. Wireless links 14are assumed to exist between the MIDI devices, and may include one ormore bi-directional (two way) links 14A and one or more uni-directional(one way) links 14B. The wireless links 14 could be low power RF links(e.g., those provided by Bluetooth hardware), or they could be IR linksprovided by suitable LEDs and corresponding detectors. Box 18, labeledContent Provider, represents a source of MIDI files to be processed bythe inventive system. Files may be transferred through any convenientmethod, e.g. over the Internet, over the telephone system, throughfloppy disks, CDs, etc. In one particular application, the data could betransmitted in real time over the internet and played as it is received.One station could receive the file and transmit it, in whole or just therelevant parts, over the wireless link or the phone system to theothers. Alternatively, the file could be received at any convenient timeand stored in one or more stations.

[0022] The above mentioned SP-MIDI specification presents a music dataformat for the flexible presentation of MIDI for a wide range ofplayback devices. The specification is directed primarily at mobilephones, PDAs, palm-top computers and other personal appliances thatoperate in an environment where users can create, purchase and exchangeMIDI music with devices that have diverse MIDI playback capabilities.

[0023] SP-MIDI describes a minimum required sound set, sound locations,percussion note mapping, controller usage, etc., thereby defining agiven set of capabilities expected of an SP-MIDI-compatible synthesizer.In general, SP-MIDI provides a standardized solution for scalableplayback and exchange of MIDI content. The Scalable Polyphony MIDIDevice 5-24 Note Profile for 3 GPP defines requirements for devicescapable of playing 5-24 voices simultaneously (5-24 polyphony devices).

[0024] Referring now to FIG. 5, there is shown a block diagram levelrepresentation of a station according to the invention. On the right,units exterior to the station are displayed-speakers 56, microphone 58,power supply (or batteries) 52 and MIDI input device 54. The powersupply may be connected only to the external speakers 56, to the otherexterior units, or to the station itself. The MIDI input device may be akeyboard, drum machine, etc. On the left of the Figure, a line of boxesrepresent various functions and the hardware and/or software toimplement them. In the center, connectors 32A and -B and 34A and -Brepresent any suitable connector for a microphone-earpiece headset thatmay be used in the invention to connect a standard mobile station toexternal devices without adding an additional connector. At the bottomleft, Storage 40 represents memory, floppy disks, hard disks, etc. forstoring data. Control 48 represents a general purpose CPU,micro-controller, etc. for operating the various components according tothe invention. Receiver 40 represents various devices for receivingsignals—the local RF link discussed above, telephone signals from thelocal phone company, signal packets from the Internet, etc. Synthesizer44 represents a MIDI or other synthesizer. Output 38 represents switches(mechanical or solid state) to connect various units to the outputconnector(s). Similarly, Input 36 represents switches (mechanical orsolid state) to connect various units to the input connector(s) as wellas analog to digital converters to convert microphone input to signalscompatible with the system, as described below. Generator 42 representsdevices to generate signals to be processed by the system; e.g. a) anaccelerometer to be used to convert shaking motions by the user tosignals that can control the synthesizer to produce maraca or otherpercussion sounds, or b) the keypad of the mobile station. Those skilledin the art will be aware that there is flexibility in block diagramrepresentation and one physical unit may perform more than one of thefunctions listed above; or a function may be performed by more than oneunit cooperating.

[0025] SP-MIDI

[0026] Before describing this invention in further detail, a morethorough discussion of certain aspects of SP-MIDI that are of mostconcern to this invention will first be made.

[0027] One aspect of SP-MIDI that pertains to this invention is referredto as channel masking. Consider a situation where a synthesizer plays aMIDI file that has a higher polyphony requirement (i.e., a highermaximum number of simultaneous playable notes) than the synthesizer cansupport. As the synthesizer is not capable of simultaneously playing allof the notes, the music playback may be partially randomized in priorpractice, depending on a note stealing method used by the synthesizermanufacturer.

[0028] An important goal of polyphony scalability is to avoid thisrandomization of music playback. If all the notes on a particular MIDIchannel cannot be played, an SP-MIDI synthesizer instead masks thatchannel, i.e., it ignores all notes on that particular channel.

[0029] Channel priorities are used to determine the MIDI channel maskingorder. In SP-MIDI, the content creator defines the priority order of thechannels, and the priorities can be subsequently revised duringplayback.

[0030] For example, the composer can place the most important materialin channels having the highest priority and the remainder of theplayback material in lower priority channels.

[0031] This ensures that the most important instruments are played, evenwith low-polyphony playback devices that are not capable of playing allof the channels.

[0032] Based on the foregoing discussion, it may be appreciated that anSP-MIDI playback device is required to have some knowledge of MIDIchannel polyphonies and priorities in order to be able to define thechannels that it is capable of playing. For this purpose anSP-MIDI-specific MIDI message is used. This message is referred toherein as a Maximum Instantaneous Polyphony (MIP) message. The MIPmessage data is used to inform the synthesizer in a source 10 or theMIDI unit 12 of the polyphonies required for different MIDI Channelcombinations within the MIDI file. The MIP may be considered as acumulative polyphony of all 16 MIDI Channels. The order of the MIDIchannel combinations is determined by the above-mentioned ChannelPriority list.

[0033] A purpose of SP-MIDI is to offer the composer enhanced controlover the playback of the music on various platforms. The composer isthen enabled to freely decide how different SP-MIDI synthesizers shouldreact to the content. Using the MIP message it is possible toincorporate multiple versions of the same high-polyphony piece of musicwithin the same SP-MIDI file. Each SP-MIDInn synthesizer plays onlythose parts in (or layers of) a song that the composer has defined to beoptimal for that polyphony. As an example, the composer can make athree-layer 24-polyphony SP-MIDI file that can be played on SP-MIDI8,SP-MIDI16, and SP-MIDI24 (SP-MIDI 8-polyphony, SP-MIDI 16-polyphony,SP-MIDI 24-polyphony) synthesizers, with different sets of instrumentalsounds to produce a pleasing composition in each synthesizer. Thus, onewould have 8-, 16- and 24-note arrangements with layers 1-8, 9-16 and17-24.

[0034] As a specific example, the composer could choose alto and tenorsaxophones, two trumpets, snare and bass drums, cymbals and bass for the8-polyphony synthesizer, thus having a first set of MIDI instructionsgiving a first part of the composition (the melody, say), to thesaxophones and trumpets, so that the music is played in the minimum caseon a first apparatus comprising the 8-polyphony synthesizer. Thecomposer would provide an option for adding a piano part (with up tofour polyphony, say) and a guitar part (also with up to four polyphony)for the 16-polyphony case. The composer would have to make a designchoice whether to merely add subordinate parts for the 16-polyphonycase, or to give the piano some of the more important music (i.e. toprovide different saxophone, trumpet and other melody parts for the8-polyphony and 16-polyphony cases). Thus, a piece of music to be playedaccording to the invention might include an 8-polyphony version having afirst saxophone part and a 16-polyphony version having a differentsaxophone part, etc. for the other instruments that normally play themelody. The term “part”, as used herein, means the music for aninstrument of a particular type, e.g. the saxophone part for a saxophonesection of up to n saxophones. The term “portion” as applied to musicmeans the melody, rhythm, etc. Thus, in a more complex system accordingto the invention, a second set of instructions allocates some of themelody portion of the music to a second set of instrumental voices(saxophone, trumpet and piano). Similarly, the rhythm portion of themusic can have versions for a limited number of voices and for a largernumber.

[0035] In addition to polyphony, the SP-MIDI standard is also defined tobe scalable. The SP-MIDI specification introduces a minimum requiredsound set, although manufacturers may expand the minimum sound set upto, for example, a full General MIDI 2.0 sound set. Any requiredinstruments that are not available are patched such that a mostsimilar-sounding of the available instruments is played instead. In thisway none of the specified musical elements are neglected due to a lackof instrument support by the playback system.

[0036] In SP-MIDI, each of the MIDI channels 10 and 11 can be used asrhythm channels. If there were only one available rhythm channel thenthe creation of scalable and good sounding musical content would becomevery difficult as the polyphony rises. Each MIDI channel, apart fromchannel 10, can be used as a melody channel.

[0037] The teachings of this section provide an entertainmentapplication that utilizes software synthesis in the context of theSP-MIDI standard. In this invention the sound processing power of two ormore sources 10 is combined in order to increase the polyphony of a songbeing played. The sources are synchronized to one another using, somesuitable wireless communication link, a LAN or the phone network. Thewireless communication link may be a low power, short-range RF link(e.g., Bluetooth), or it may be an IR optical link. The synchronizedsources 10 play different portions of the same MIDI file according torules specified by SP-MIDI. Each source 10 may have a different set ofsounds (instruments) all of which are assumed to adhere to the SP-MIDIspecification. Both polyphony and the quantity of available sounds aretherefore summed together.

[0038] In the typical case each SP-MIDInn synthesizer plays only thoseparts of a song that the composer has defined to be optimal for thatpolyphony. In one example, a composer might create a three-part,24-polyphony SP-MIDI file that can be played on SP-MIDI8, SP-MIDI16 andSP-MIDI24 synthesizers. An individual terminal may, if it has enoughmemory, store the whole composition. Alternatively, it may receive onlythe data that it will be playing.

[0039] In accordance with an aspect of this invention, the 24 notes ofthis example are partitioned between the available sources 10. If thereare, for example, two sources 10 available that have SP-MIDI8capability, the first SP-MIDI8 source plays the first eight notesaccording to the Channel Priority Order, and the second SP-MIDI8 sourceplays the next eight notes. If a third source 10 later joins the groupof two sources, it is assigned to play the remainder of the 24 notes.Thus the full 24 note composition can be played, even though not one ofthe participating sources has a synthesizer capable of playing more thaneight notes.

[0040] The teachings of this invention thus provide for grouping severaldevices together to create a musical sound environment that is common toall the devices. Each source 10 and/or MIDI device 12 is assumed to haveat least one (internal or external) speaker. The source(s) 10 and/orMIDI device(s) 12 are preferably located in the same space so that everyuser hears the sound output from all of the devices. Each device isgiven a unique ID for differentiating that device from other devices inthe group of devices, thereby providing the ability to inform thedevices as to which layers of the SP-MIDI file they should play.

[0041] By the use of this invention the sounds of multiple MIDI devicesare combined into one shared sound environment. The use of thisinvention relieves the high computational requirements of softwaresynthesis by partitioning the processing load between at least twoSP-MIDI-compatible sources 10 and/or MIDI devices 12. Both the polyphonyand the quantity of available sounds are therefore summed together.

[0042] The use of this invention automatically allocates different MIDIchannels between the sources 10 and/or MIDI devices 12. Furthermore, aseparate controlling host operation is not required, as embeddeddecentralized control is provided by the participating sources 10 and/orMIDI devices 12 and their communication over the local area wirelessnetwork that is implemented using Bluetooth or some other suitabletechnique. The actual sound output is generated through each source 10speaker 10A, though a common mixer and speakers could also be used.

[0043] The teachings of this invention solve the problem of the highcomputational requirements of software synthesis by splitting theprocessing load between two or more sources 10. This enables higherpolyphony music to be played and enjoyed in a group situation. Theactual sound is improved and additional voices are enabled to be heard.The addition of devices with enhanced sound banks further improves thesound. Certain instruments can be multiplied by playing them with morethan one source 10.

[0044] The MIDI-related services can be downloaded to users over theair, and basic ringing tone MIDI files and the like can be used so thatadditional effort by content creators may not be required.

[0045] Before the playback can begin, the sources 10 are synchronized toeach other by using, for example, Bluetooth. Preferably, thesynchronization continues through the playing. If the sources 10 havetiming that is sufficiently good, the synchronization information couldbe sent only at the beginning of playing. When several devices are usedto create the shared sound environment, each of them is uniquelyidentified in order to be able to resolve which device plays whichSP-MIDI layer. It is possible to implement the process to be totallyautomatic or user controllable.

[0046] Discussing first the totally automatic mode, heuristicsimplemented in the system select which parts of the music, sometimesreferred to as layers, are played by which synthesizer. Referring toFIG. 2, it can be seen that each source 10 includes a synthesizer 20coupled with a controller 22 (which may be a general purpose or specialpurpose computer) that operates in accordance with this invention, andthat receives information from at least one other controller 22 via awireless link 24, such as Bluetooth. This is done automatically afterthe shared sound playing is enabled in the source 10, and anotherSP-MIDI-enabled source 10 is detected in the immediate environment.

[0047] In the user controllable mode, a relatively simple user interface(UI) 26 is provided for enabling the selection of which channels areplayed by which source 10. One alternative is that one source 10 of thegroup assumes the role of a master device, and sets the IDs for eachdevice as they join the group. The ID numbers can be assigned in orderof joining the group, or at random, and they determine which MIDIchannels (i.e. which SP-MIDI layer or musical part) the device shouldplay.

[0048]FIG. 3 shows an example of starting an application and assigningthe IDs to various one of the sources 10 of the group. At Step A theapplication is begun, and at Step B one of the sources 10 assumes therole of the master device and reserves a master device ID. As examples,this source 10 could be the first one to join the group, or one selectedby the users through the UI 26. As other sources 10 enter the spaceoccupied by the group (e.g., a space defined by the reliabletransmission range of the wireless link 24, that is also small enoughfor the sound from all devices to be heard by all participating sources10) the new device attempts to enroll or register with the group (StepC). If accepted by the master device an acknowledgment is sent, as wellas the new sourcc=s MIDI group ID (Step D). At some point, if playinghas not yet begun, the group is declared to be full or complete (StepE), and at Step F the group begins playing the music, where each source10 plays only its assigned layer. The end result is a substantialincrease in polyphony without a corresponding increase in computationalload and power consumption for any one particular source.

[0049] If there are more willing participants than there are availableSP-MIDI layers, some layers can be assigned to two or more sources 10.

[0050] While described in the context of certain presently preferredembodiments, the teachings in accordance with this invention are notlimited to only these embodiments. For example, the wireless connectionbetween terminals 10 can be any suitable type of low latency RF oroptical connection (wireless or cable) so long as it exhibits thebandwidth required to convey messages between the participating sources.Further in this regard the link could be made through any suitableconnection, including the Internet.

What is claimed is:
 1. A method for playing music, comprising: providinga musical composition having i note polyphony; and playing the musicalcomposition with at least two sources of a group of sources, where afirst source is assigned to play j notes and a second source is assignedto play k notes, where j<i and k<i, and where the notes are assigned ina Channel Priority Order.
 2. A method as in claim 1, where the k notesduplicate some or all of the j notes assigned to the first source.
 3. Amethod as in claim 1, where j+k<i, and further comprising assigning athird source l additional notes to play of the musical composition.
 4. Amethod as in claim 1, where j+k=i, and further comprising assigning athird source l notes to play of the musical composition, where the lnotes duplicate all or some of the j or k notes played by the first orsecond sources.
 5. A method as in claim 1, where the j and k notes areplayed simultaneously, and further comprising an initial step ofsynchronizing the first source to the second source.
 6. A method as inclaim 1, where the j and k notes are played simultaneously, and furthercomprising an initial step of synchronizing the first source to thesecond source by communications made through a wireless local network.7. A method as in claim 6, where the wireless local network comprises anRF network.
 8. A method as in claim 7, where the RF network comprises aBluetooth network.
 9. A method as in claim 6, where the wireless localnetwork comprises an optical network.
 10. A method as in claim 1, whereone of the at least two sources functions as a group master, and assignsan identification within the group to the other source or sources.
 11. Amethod as in claim 6, where one of the at least two sources functions asa group master, and assigns an identification within the group to theother source or sources using said wireless local network.
 12. A systemcomprising a group of sources coupled together through a local wirelessnetwork, said system being responsive to a presence of a musicalcomposition having i note polyphony for partitioning the musicalcomposition such that it is played by at least two sources of the group,said system including a controller operating in accordance with aChannel Priority Order such that a first source is assigned to play jnotes and a second source is assigned to play k notes, where j<i andk<i.
 13. A system as in claim 12, where the k notes duplicate some orall of the j notes assigned to the first source.
 14. A system as inclaim 12, where j+k<i, and further comprising a third source that isassigned to play l additional notes of the musical composition.
 15. Asystem as in claim 12, where j+k=i, and further comprising a thirdsource that is assigned to play l notes of the musical composition,where the l notes duplicate all or some of the j or k notes assigned tothe first or second sources.
 16. A system as in claim 12, where the jand k notes are played simultaneously, and further comprising means forsynchronizing the first source to the second source through saidwireless local network.
 17. A system as in claim 12, where said wirelesslocal network comprises an RF network.
 18. A system as in claim 17,where said RF network comprises a Bluetooth network.
 19. A system as inclaim 12, where said wireless local network comprises an opticalnetwork.
 20. A system as in claim 12, where one of the at least twosources functions as a group master for assigning an identificationwithin the group to the other source or sources using said wirelesslocal network.
 21. A source, comprising a wireless transceiver coupledto a controller and a synthesizer that has an output coupled to aspeaker, said controller being responsive to a composition having n notepolyphony for controlling said synthesizer for playing, in wirelesssynchronism with at least one other source, m notes of the composition,where m <n, and where said at least one other source plays additionalnotes of the composition.
 22. A source as in claim 21, where saidwireless transceiver comprises a Bluetooth transceiver.
 23. An articleof manufacture comprising a program storage medium readable by a firstcomputer having a memory, the medium tangibly embodying: at least twosets of instructions for playing a musical composition through acomputer device that is processing the instructions, a first set ofinstructions playing a first portion of the composition with a first setof electronic apparatus of N polyphony and a second set of instructionsplaying said first portion of the composition with a second set ofelectronic apparatus having M polyphony, where M>N; and at least one setof control instructions to said first computer, controlling said firstcomputer to employ said first set of instructions when playing saidcomposition with equipment of N polyphony and to employ said second setof instructions when playing said composition with equipment of Mpolyphony, whereby said first portion of the composition may be playedwith more instrumental voices in said second electronic apparatus. 24.An article of manufacture according to claim 23, in which said secondset of electronic apparatus comprises said first set of electronicapparatus plus at least one additional electronic apparatus.
 25. Anarticle of manufacture according to claim 24, in which said first setcomprises at least one mobile terminal and said second set comprises atleast two mobile terminals.